Metal-petticoat insulator.



UNITED STATES PATENT onnronl .KABL C. RANDALL, 0F EDGEWOOD PAIR-11,1 PENNSYLVANIA, ASSIGNOR 'IO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, -.A CORPORATION OF PENNSYL- VANIA.

mn'rAL-rnrrIcoA'r INSULATOR.

To all iohom it may concern:

Be it known that I, KARL G. RANDALL, a

form a builtup structure of any number of units.

From the .d'landpoint of economical construction and ease in replacing injured members, it is desirable to build. an insulator comprising units of uniform design which may be conveniently and expeditiously relaced when any one of them becomes inured or deteriorates with respect to its insulating strength. Heretofore, high-voltage insulating supports usually consisted of a number of porcelain members of substantially uniform construction which were superposed on, and secured to, one another by means of cement or some other suitable binder. When a member of such a support was broken or impaired as a result (if a highvoltage fiashover, it was frequently necessary to scrap the entire insulating support because of the impossibility of replacing the injured member only. Since insulating suports are liable to serious injury resulting m their being exposed to severe mechanical, as well as electrical, stresses, the expense of maintaining and replacing porcelain insulators for supporting high-voltage transmission lines is considerable.

By means of my invention, an insulating support is provided that is suificiently rigid .in construction to withstand any usual mechanical stresses to which it is liable tobe subjected. A ain, the units comprising my support are 0 uniform construction and so secured to one another as to permit their being expeditiously detached or replaced when necessary to make repairs on, or substitutions for, defective units. Moreover, each of the unitsfispso designed as'to substantially preclude the concentration of electrostatic Specification of Lettersratent.

Patented Mar. 12, 1918.

Application filed August 6, 1915. Serial No. 43,977.

lines of force thereupon, and the bodies of air interposed between the elements to be insulated from one another are utilized to their full insulating strength, thereby permitting of an economical construction.

For a better understanding of the nature and scope of my invention, referencemay be had t6 the following description and the accompanyingdrawing in which Figure. 1 is a View, partially in elevation and partially in section, of an insulator embodying a form of my invention, and Figs. 2 and 3 are crosssectional views that show methods of reinforcing the metal petticoats of the insulating support of Fig. 1.

Referring to Fig. 1, a metallic support 1, which is adapted to be mounted upon a transmission tower or pole (not shown), projects into the interior of a conducting unit 2 which constitutes the lowermost conducting member of my insulating support. Units 3 and 4, which are of uniform construction, are superposed upon, and secured to, one another, as will be hereinafter explained, in order to provide a built-up structure of the desired insulating strength. A clamp 5 mounted upon the uppermost unit 4 provides means for attaching the transmission line conductor (not shown) which it is desired to insulate.

Each of the units 3-4 comprises a metallic bell-shaped petticoat 5 which is outwardly flared at its bottom portion and which substantially envelopsan insulating body 6, preferably made of any suitable insulating compound that is capable of being molded. A deeply indented recess 7 is centrally disposed in eachof the insulating bodies 6, and is adapted to receive a lower insulator unit of a design similar to that of the upper insulator unit. A stud 8, provided with an enlarged head portion and a threaded shank, is embedded in the insulating body 6 in such manner that the threaded shank extends downwardly and engages a threaded sleeve or nut 9 which is disposed in the upper portion of a lower insulator unit. The recess 7 is preferably formed by.

means of a mold of suitable contour which posed in the upper portion of a lower insulator unit.

When it is desired to minimize the overall length of my. insulator, and to operate at maximum efficiency, the bodies of air interposed between adjacent metallic petticoats should be utilized to their full insulating value. In accordance therewith, the exposed surfaces 10 of the insulating bodies 6 are so shaped as to substantially conform to the electrostatic flow lines constituting the ex ternal electrostatic field extending between adjacent conducting members. At the same time, the outwardly flared lower portions of the metallic petticoats substantially preclude the concentration of electrostaticfiow lines upon the insulator and, consequently, greatly enhance its insulating strength.

The supporting pin 1 is drilled and threaded at its upper end in order to cooperatively engage the threaded shank of the stud 11 secured to the insulator unit 3. A body of filler or cement 12 is then poured around the pin 1, thereby holding it in fixed relationship with respect to the lowermost conducting petticoat 3. At the same time, an exposed surface 14 of the'body 12 .is so shaped as to form a continuation of the exposed surface 10 of the insulating body 4. The clamp 5 is secured to the uppermost insulating unit 4 by providing an eye bolt 15 which engages 'the metallic nut 9. A rod 16, projecting through the eye bolt, holds the cap 5 in'position upon the metallic member 5 of the insulating unit 4. The clamp 5 is recessed to closely engage the tapered upper portion of the metallic petticoat 4.

Under certain service conditions, it may be necessary to reinforce the lower edges of the metallic Petticoats 5 and, to this end, the structures shown in Figs. 2 and 3 are proposed in order to reinforce the peripheries of the metallic petticoats. In Fig. 2, the metallic petticoat 5 is provided with a bead 17 which is formed in any usual and well known manner. In Fig. 3, a circular rod 18 is bent to conform to the periphery of the petticoat 5 and may be welded thereto so as to lend additional support and stiffness to the conducting petticoat.

While I have shown and described, in detail, an embodiment of my invention, it will be understood by those skilled in the art that many modifications may be made without departing from the spirit and scope of the appended claims;

I claim as my invention:

1. An insulator comprising nested metal members of bell shape having detachable flaring projections extending from the domes thereof, and bodies of insulating material disposed between the said metal members and embracing the said projections to hold the said metal members together.

2. An insulator comprising nested metal therewith embedded in t sion conductor engaging said bodies of insulating material having exposed surfaces conforming to the direction of the static field.

3. An insulating structure comprising a plurality of superposed and nested units each having a bell-shaped conducting member which substantially surrounds an insulating body provided with a recess that is adapted to receive the next succeeding unit, studs embedded in the deeply-indented portions of said recesses of the upper units, and threaded sleeves to 006 eratively engage therewith embedded in the upper portions of the lower units.

4. An insulating structure comprising a plurality of superposed and nested units each having a bell-shaped conducting member which substantially surrounds an insulating body provided with a recess that is ada ted to receive the next succeedin unit, stu s embedded in the deeply in ented portions of said recesses of the upper units, threaded sleeves to cooperative y engage therewith embedded in the upper portions of the lower units, and a clam for a transmission conductor engaging t e uppermost threaded sleeve.

5. An insulating structure comprising a plurality of superposed and nested units each having a bell-shaped conducting mem ber which substantially surrounds an insulating body provided with a recess that is ada ted to receive the next succeeding unit, stud; embedded in the deeply-indented portions of said recesses of the upper units,

threaded sleeves to cotiperatively engage e upper portions of the lower units, a clamp for a transmisthe uppermost threaded sleeve, and a rigid supporting pin engaging the lowermost stud.

6. An insulator comprising nested metal members of bell shape having relatively small openings in the domes thereof, members having relatively large end portions and restricted mid portions severally disposed with their enlarged portions on either side of the said 0 enings, and bodies of insulating materia disposed substantially surrounding the said enlarged portions and between the said members of bell shape to hold the latter together.

7. An insulator comprising nested members of bell shape having relatively small openings in the domes thereof, members having relatively large endportions and a restricted mid portion disposed in the said openings, the said end portions bein separable, and bodies of insulating material dis- 1 posed around the said end portions and abutand nut are embedded disposed in the said 10 ting the said nested members to hold the dome, and a pin extending transversely latter together. through all of the said members to hold the 8. An insulator comprising a metal memconductor-supporting member in position. 5 her of bell sha e, an eye-bolt member hav- In testimony whereof, I have hereunto ing a threade shank disposed inside the subscribed my name this 27th day of July, 15 dome of, andcoaxially with, the said bell 1915.

member, a. nut for the shank, a body of insulating material in which the said eye-bolt' KARL O. RANDALL. 

